SQL funtion

Hi All,
I have written a very simply function as follows:
create function song_info(int4) returns setof songs as'
select songs.* from songs
where $1=song_id'
language 'sql';
when iIcall it I get the following: flipr=# select song_info(4);
?column?
-----------
136428992
(1 row)

Is not it suppose to retrun me the tuple form songs table rather than
oid....
If I want to get a complete tuple what can I do.
Thank you all for your help.
Regards, Najm.